Wietse Venema: > Joe Postfix: > > Does anyone know if postfix supports a feature equivalent to > > relay_based_on_MX in sendmail? > > Wietse: > > Yes. > > > > However such features must not be used because they accept mail > > for non-existent recipients, and therefore 1) they fill the Postfix > > queue with non-deliverable MAILER-DAEMON messages, and 2) the > > MAILER-DAEMON messages that can be delivered will bother innocent > > people about mail that they did not send. > > Joe Postfix: > > Can you explain how this feature could be enabled? > > > > One of our the services we offer our customers allows them to create as many > > domains as they like (on various DNS's), and we have a catchall mailbox that > > grabs any emails sent to those domains. > > What happens when a spammer points an MX record at your server?
Postfix can be configured with permit_mx_backup to accept mail if any MX records points to the MTA, but unfortunately this feature is unsafe because it is so easy to abuse, and for this reason I would like to remove it in the future. > Wietse > > > Of course you are correct most of the content on there is spam (at times, > > over %90), but certain campaigns will have our customers sifting through > > those mountains of spam for accountability purposes, etc. > > > >
